Do I have possible US Imigration problems?

During my last visit to he USA, in April 2002, my green immigration card( a 3 month tourist one, not the “green card” ) was not removed (by the airline staff) from my pasport. I never noticed untill last week when I got a new pasport. Is this giving problems when entering the USA in the futore, or better said, am I now possible in the computer as an “Illegal Alien” since April 2002? In the old days this should not have bothered me, but a friend with more or less the same problem spent an interesting night, together with some very “interesting” company behind bars in Miami, before things were sorted out, and he was lucky to enter the USA after all. Anyone having an advise what to do, or can give me an emailadress or something at the immigration? The US embassy wasn’t very helpfull, so I have to sort out the problems by myself. BW Roger